On Fri, 17 Apr 2020, Jakub Jelinek wrote: > On Fri, Apr 17, 2020 at 09:24:34AM +0200, Richard Biener wrote: > > --- a/gcc/optabs.c > > +++ b/gcc/optabs.c > > @@ -1050,7 +1050,7 @@ expand_binop_directly (enum insn_code icode, > > machine_mode mode, optab binoptab, > > commutative_p = commutative_optab_p (binoptab); > > if (commutative_p > > && GET_MODE (xop0) != xmode0 && GET_MODE (xop1) != xmode1 > > - && GET_MODE (xop0) == xmode1 && GET_MODE (xop1) == xmode1) > > + && GET_MODE (xop0) == xmode1 && GET_MODE (xop1) == xmode0) > > Do we need 4 comparisons for that? Wouldn't > if (commutative_p > && xmode0 != xmode1 > && GET_MODE (xop0) == xmode1 > && GET_MODE (xop1) == xmode0) > std::swap (xop0, xop1); > be more readable and shorter?
Not sure - xmode[01] are derived from insn_data while xop[01] are passed in as arguments so it seems the code wants to check the modes are not fine already, not whether swapping is a no-op because both are equal. Thus I went for the obvious change at this point. Richard.
